Not Applicable
Not Applicable
Not Applicable
This invention relates to starters (cranking motors) for piston aircraft engines equipped with ring-gears driven by the starter. Original equipment starters incorporated centrifugal engagement of the starter pinion gear with the engine ring-gear. This engagement method, referred to as xe2x80x9cBendix drivexe2x80x9d systems, were used on automobiles in the period of 1930-1950 and were replaced by solenoid engagement in that application due to the inherent unreliability of the centrifugal engagement system. A starter similar to this invention is known from U.S. Pat. No. Des. 360,638 (Sky-Tec) which utilized a solenoid engagement mechanism in conjunction with a DC motor and gear-reduction unit. The starter identified in U.S. Pat. No. Des. 360,638 provided greater reliability but only fits engines in aircraft that can accommodate a starter width dictated by sum of the diameters of the solenoid engagement mechanism and that of the DC motor located side-by-side. This diameter is too large to fit the available space in many existing aircraft designs.
It is, therefore, an objective of this invention to overcome the disadvantages of the previous art through realignment of the major components to provide a starter with a diameter no wider than that of any previous art while increasing reliability over earlier, centrifugally engaged, starters.
The original equipment starters fitted to the subject aircraft engines, notably those engines produced by Lycoming, utilized centrifugal engagement mechanism (Bendix-drives) located on the shaft of a DC motor or driven by such a motor through an offset gearing arrangement. This prior art has been insufficient in reliability and many attempts have been made to replace the centrifugal engagement mechanism with more reliable solenoid engagement. All of these attempts have fallen short of the goal of being suitable to replace all of the original equipment starters, as many aircraft installations were designed in such a manner that no starters wider than the original will fit in the space allocated.
To obtain the objective of increased reliability without increase in diameter or size in any other dimension, a novel construction has been employed in the starter that is the subject of this invention: A pinion gear and one-way clutch assembly is located at the front of the starter. Immediately behind this assembly is an electromechanical solenoid containing a plunger which pushes the pinion forward to engage the engine""s ring-gear. Finally, a DC motor is located behind the solenoid and drives the clutch and pinion assembly via a gear-shaft that passes by the solenoid.
This novel construction, hereinafter called the, xe2x80x9cin-Linexe2x80x9d starter, results in a starter that incorporates the reliability of solenoid engagement with the small diameter of earlier, centrifugally engaged, starters.